JP4430408B2 - Ball joint - Google Patents

Description

  The present invention has a ball stud having a spherical head and a handle extending from the head, a bearing for swingably supporting the head of the ball stud, and an opening from which the handle of the ball stud protrudes. And a ball joint including a housing for supporting the bearing.

A ball joint in which a synthetic resin bearing is supported inside a housing and a spherical head of a ball stud is slidably fitted to the bearing is known from Patent Document 1 below.
JP-A-8-128438

  By the way, in order to operate the ball joint smoothly, it is necessary to reduce the frictional resistance between the bearing and the head of the ball stud, but the sliding between the bearing and the head of the ball stud is necessary to reduce the frictional resistance. If the area of the surface is reduced, the surface pressure of the sliding surface due to the load increases, and the wear of the bearing is promoted, so that the durability of the ball joint is lowered.

  The present invention has been made in view of the above-described circumstances, and an object thereof is to increase durability against a load while reducing the frictional resistance of a ball joint.

To achieve the above object, according to the first aspect of the present invention, a ball stud having a spherical head and a handle extending from the head, and the head of the ball stud are swingably supported. In a ball joint including a bearing and a housing that supports the bearing with an opening from which a handle portion of the ball stud protrudes, the housing is provided at an end of a suspension arm of a vehicle. The longitudinal direction is a load transmission direction, and extends in the axial direction of the bearing, opens to the opening side, and has four slits arranged at a position shifted by 45 ° with respect to the load transmission direction around the axis. an annular grease groove extending in a direction perpendicular to the slit on the inner peripheral surface of the bearing is provided, wherein the grease groove ball stud and base Between the rings, among the four locations which are defined by the slits, a first grease groove provided in the compartment of the two locations of the load transmission direction and a second grease grooves provided in the section of the other two locations The first grease groove and the second grease groove are formed such that the end face on the opening side has the same height in the axial direction, and the groove width of the first grease groove is the groove width of the second grease groove. By making it narrower, the area of the sliding surface of the head and the bearing located in the load transmission direction between the ball stud and the bearing is made larger than the area of the sliding surface located in the other direction. A ball joint characterized by this is proposed .

  In addition, the 1st, 2nd sliding surfaces 14b and 14c of an Example respond | correspond to the sliding surface of this invention, and the 2nd opening part 17 of an Example respond | corresponds to the opening part of this invention.

  According to the configuration of the first aspect, the area of the sliding surface of the head and the bearing positioned in the load transmission direction between the ball stud having the spherical head and the bearing is the sliding positioned in the other direction. Since the total area of the sliding surface is minimized, the frictional resistance is reduced and the ball stud can be smoothly swung, while the sliding surface located in the load transmission direction is reduced. By ensuring the area, the surface pressure can be reduced and the durability against wear can be enhanced.

  In particular, the grease groove has a first grease groove provided in the load transmission direction between the ball stud and the bearing, and a second grease groove provided in the other direction, and the groove width of the first grease groove is set to the first width. Since it is formed narrower than the groove width of the two grease grooves, the area of the sliding surface located in the load transmission direction can be made larger than the sliding surface located in the other direction.

  Moreover, since the ball joint housing is provided at the end of the suspension arm of the vehicle, the load from the road surface transmitted in the longitudinal direction of the suspension arm can be received by a wide sliding surface. Thereby, while ensuring the durability of the ball joint, the suspension arm can be smoothly swung to improve the riding comfort of the vehicle.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below based on examples of the present invention shown in the accompanying drawings.

  1 to 6 show an embodiment of the present invention. FIG. 1 is an overall side view of a suspension arm, FIG. 2 is a partially enlarged sectional view of FIG. 1, and FIG. 3 is a ball joint corresponding to FIG. 4 is an enlarged sectional view taken along line 4-4 of FIG. 2, FIG. 5 is a longitudinal sectional view of the bearing (sectional view taken along line 5-5 of FIG. 6), and FIG. 6 is a sectional view taken along line 6-6 of FIG. is there.

  As shown in FIGS. 1 to 4, a rubber bush joint 9 connected to a vehicle body (not shown) and a ball joint 12 connected to a knuckle (not shown) are provided at both ends of a suspension arm 10 of the automobile. The ball joint 12 includes a ball stud 13 including a spherical head portion 13a, a handle portion 13b extending integrally from the head portion 13a, and a male screw portion 13c formed at the tip of the handle portion 13b. The periphery of the head 13 a of the ball stud 13 is covered with a synthetic resin bearing 14 having a small friction coefficient, and the head 13 a of the ball stud 13 can swing with respect to the bearing 14. The male thread portion 13c of the ball stud 13 is fastened to the knuckle with a nut. A housing hole 15 is formed in the housing 11 provided at the tip of the suspension arm 10, and both ends of the housing hole 15 open on both surfaces of the suspension arm 10 at the first opening 16 and the second opening 17.

  When assembling the ball joint 12, the male screw portion 13 c and the handle portion 13 b of the ball stud 13 are penetrated from the first opening portion 16 having a diameter larger than that of the storage hole 15 to the second opening portion 17. The bearing 14 covering the portion 13 a can be fitted into the storage hole 15. At this time, since the diameter of the second opening 17 is smaller than the diameter of the bearing 14, the bearing 14 does not fall out of the second opening 17.

  Subsequently, with the disk-shaped plug 18 inserted from the first opening 16 being supported by the step portion 19 between the first opening 16 and the storage hole 15, the first opening 16 is directed radially inward. By caulking and pressing the plug 18, the plug 18 is fixed to the first opening 16 of the suspension arm 10 as shown in FIG. 2. Then, both ends of the boot 20 that prevent the intrusion of dust and moisture while allowing the ball stud 13 to swing are fixed to the tip of the handle portion 13 b of the ball stud 13 and the periphery of the second opening portion 17.

  5 and 6 together, the synthetic resin bearing 14 is provided with four slits 14a... That open to the second opening 17 side of the housing 11 of the suspension arm 10 at intervals of 90 °. The head 13a of the ball stud 13 can be fitted inside the bearing 14 by elastically opening these slits 14a.

  The inner peripheral surface of the bearing 14 that slides in contact with the head portion 13a of the ball stud 13 has two first sliding surfaces 14b, 14b and two second sliding surfaces 14c, by four slits 14a. 14c. The first sliding surfaces 14b, 14b and the second sliding surfaces 14c, 14c are alternately arranged, and the two first sliding surfaces 14b, 14b facing each other are in the longitudinal direction of the suspension arm 10 (load transmission direction). ) And the two second sliding surfaces 14c, 14c facing each other are arranged in a direction perpendicular to the second sliding surfaces 14c, 14c. The first sliding surfaces 14b, 14b are formed with first grease grooves 14d, 14d extending in a direction orthogonal to the slits 14a, and the second sliding surfaces 14c, 14c are second extending in a direction orthogonal to the slits 14a. Grease grooves 14e and 14e are formed. The groove widths of the first grease grooves 14d and 14d are narrower than the groove widths of the second grease grooves 14e and 14e. Therefore, the sliding areas of the first sliding surfaces 14b and 14b are the second sliding surfaces 14c and 14c. It is wider than the sliding area. As is apparent from FIGS. 5 and 6, the first grease grooves 14 d and 14 d and the second grease grooves 14 e and 14 e are formed in an annular shape so as to surround the axis of the bearing 14 as a whole.

  Thus, when the suspension arm swings up and down as the vehicle travels, the bearing 14 fixed to the housing 11 of the suspension arm 10 swings relative to the head 13a of the ball stud 13 fixed to the knuckle. To do. At that time, the first sliding surfaces 14b and 14b and the second sliding surfaces 14c and 14c are lubricated by the grease held in the first grease grooves 14d and 14d and the second grease grooves 14e and 14e formed on the inner surface of the bearing 14. The

  Since the groove width of the second grease grooves 14e and 14e is made larger than the groove width of the first grease grooves 14d and 14d, the total area of the first and second sliding surfaces 14b and 14b; 14c and 14c is correspondingly increased. The sliding resistance can be reduced and the suspension arm 10 can be smoothly swung to improve the riding comfort of the vehicle. The suspension arm 10 is subjected to a compressive load or a tensile load in the longitudinal direction thereof, but the first sliding surfaces 14b, 14b supporting the load are reduced by reducing the groove width of the first grease grooves 14d, 14d. Can be secured sufficiently, and the surface pressure of the first sliding surfaces 14b, 14b can be reduced to enhance the durability of the bearing 14. Thus, by reducing the area of the sliding surface between the head 13a of the ball stud 13 and the bearing 14 in the circumferential direction in accordance with the direction of the load, both reduction in frictional resistance and improvement in durability are achieved. It becomes possible to do.

  Although the embodiments of the present invention have been described above, various design changes can be made without departing from the scope of the present invention.

Overall side view of suspension arm Partially enlarged sectional view of FIG. Exploded view of the ball joint corresponding to FIG. 4-4 enlarged cross-sectional view of FIG. Longitudinal sectional view of bearing (sectional view taken along line 5-5 in FIG. 6) 6-6 sectional view of FIG.

10 Suspension Arm 11 Housing 13 Ball Stud 13a Head 13b Handle 14 Bearing 14a Slit 14b First Sliding Surface (Sliding Surface)
14c Second sliding surface (sliding surface)
14d First grease groove 14e Second grease groove 17 Second opening (opening)

Claims (1)

A ball stud (13) having a spherical head (13a) and a handle (13b) extending from the head (13a);
A bearing (14) for swingably supporting the head (13a) of the ball stud (13);
A housing (11) having an opening (17) from which the handle (13b) of the ball stud (13) protrudes and supporting the bearing (14);
In ball joints with
The housing (11) is provided at the end of the suspension arm (10) of the vehicle,
The longitudinal direction of the suspension arm (10) is the load transmission direction,
There are four slits (14a) that extend in the axial direction of the bearing (14), open to the opening (17) side, and are arranged at a position shifted by 45 ° with respect to the load transmission direction with the axis as the center. An annular grease groove extending in a direction orthogonal to the slit (14a) is provided on the inner peripheral surface of the bearing (14),
The grease groove is a first grease groove provided in two sections in the load transmission direction among the four sections partitioned by the slit (14a) between the ball stud (13) and the bearing (14). (14d) and a second grease groove (14e) provided in the other two compartments ,
The axial heights of the end faces of the first grease groove (14d) and the second grease groove (14e) on the opening (17) side are formed to be equal,
By forming the groove width of the first grease groove (14d) narrower than the groove width of the second grease groove (14e), the first grease groove (14d) is positioned in the load transmission direction between the ball stud (13) and the bearing (14). The ball joint is characterized in that the area of the sliding surface (14b) of the head (13a) and the bearing (14) is larger than the area of the sliding surface (14c) located in the other direction .

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